DieselShip's Online Content Library

Q1. With reference to membrane tanks for the carriage of liquefied gas at very low temperatures. A. Describe with a sketch one method of building up the insulation; B. State which alloy is used for the membrane and the reason; C. Describe with the aid of a sketch, how the tanks are located and supported. i) Longitudinally; ii) Transversely

Q3: With reference to dry docking, define the responsibility of the second engineer;

A. Prior to docking;

B. Whilst the vessel is in dry dock;

C. Prior to flooding and leaving the dock.

Q3. A. Explain what is meant by permissible length of compartments in passenger ships;

B. Describe how the position of bulkheads is determined.

C. Describe briefly the significance of the factor of subdivision.

Q5. Explain how the period of roll varies with –

A. The amplitude of roll;

B. The radius of gyration;

C. The initial metacentric height;

D. The location of masses in the ship.

Q1. Describe the relationship between frictional resistance and

(a) Ship’s speed;

(b) the wetted area;

(c) surface roughness;

(d) The length of the vessel.

Q8. A. Why is it important in a tender ship to keep the double bottom tanks pressed up?

B. A ship of 6000 tonne displacement has a wetted surface area of 2500 m2 and a speed of 15 knots.

(i) Calculate the corresponding speed and wetted surface area of as similar ship of 2000 tonne displacement.

(ii) If the ship resistance is of the form R=0.45 S V1.83 N; find the resistance of the 6000 tonne Ship.

Q10. A box-shaped vessel is 20 m long and 10 m wide.  The weight of the vessel is uniformly distributed throughout the length and the draught is 2.5 m.  The vessel contains ten evenly spaced double bottom tanks, each having a depth of 1m. Draw the shear force diagrams:

With No.1 and No.10 tanks filled; With No.3 and No.8 tanks filled; With No.5 and No.6 tanks filled.

Which ballast condition is to be preferred from the point of view of strength?

Q7. A. what is the effect on fuel consumption per unit time, if the ship’s speed is outside its operation range? B. The frictional resistance of a ship in fresh water at 3m/s is 11N/m2.  The ship has a wetted surface area of 2500m2 and the frictional resistance is 72% of the total resistance and varies as speed 1.92.  If the effective power is 1100Kw, calculate the speed of the ship.

Q9. A. Describe the procedure for speed, Power and fuel consumption trials. B. A propeller of 4m pitch has an efficiency of 67%.  When turning at 125 rev/min the real slip is 36% and the delivered power 2800Kw.Calculate the thrust of the propeller.

Q10. A. Explain the considerations which govern the size and shape of a rudder. B. A ship of 12000 tonne displacement has a rudder 15m2 in area, whose centre is 5m below the waterline.  The metacentric height of the ship is 0.3m and the centre of buoyancy is 3.3m below the waterline.  When travelling at 20 knots the rudder is turned through 30 .  Find the initial angle of heel if the force Fn perpendicular to the plane of the rudder is given by: Fa=577 Av2 sin  N, Allow 20% for the race effect.